Testing apparatus for link trainer recorders



Aug. 21, 1945. s. MARSHALL 2,383,006

` TESTING APPARATUS FQR LINK TRAINER RECORDERS Filed Sept.l 5, 1945 2sheets-sheet 1 IN VEN TOR ELAv/va 6. MeSH/4L A TTORNE Yi Flc. i

L. s. MARSHALL 2,383,006

TESTING APPARATUS FOR LINK TRAINER REORDERS Filed Sept. 3, 1943 2Sheets-Sheet 2 Aug. 2l, 1945.

INVENTOR .L-JN0 J. Mwesaqca. I BY de' u ATTORNEYJ Patented Aug. 21,`1945 www ` "TEsTINGlPPAaTUs FOR LINK TRAINER f h gnEooRDERs h e y,LelandSrMarshall, Dayton, Ohio y e Application september 3, 1943, serial Nc.501,127

` fllClaims. (Cl. 73-`-1) fiori-antec under `thc 'act cf Marche, 1883',as

amendedApril 30,w1928; 370 Q. G."45"7)V The invention described hereinmayfbe manu# factured and usedby` or forthef Government for governmentalpurposes,V without" the "payment to me of any royalty thereon. l `Thisinvention'relates to apparatus for testing the accuracy of the iiight`log or recorder which makes `a `graphic record Iof the `course iown bya'student ina Link trainer. Reference maybe made to 'BritishPa'tent'Na484,243 to E. A; Link, Jr., or Link Patent No. 2,179,663,datedcNovernber 14,1939, i

`The Link' trainer is an aviationtrainingdevice wherein a fuselage,having acockpit for'the stu-y dent, is provided with controls similar'inappearance and action to those of an airplane, and also has aircraftinstruments and radio apparatus, making it possible? to simulate nearlyevery condi#` tion or operation which may arise during a flight,` Thestudent flies the trainerunder ahood, on instruments; followinginstructions frorhan in-A structor,` who sits'alt"a"des`k` inthe saineVrocfirri in which the trainer is set up.` Onthe desk top is the flightMlog or recorder, which travels `very slowly 0.875 or% in fper min.)marking on paper or plastic sheets an ink iiricwhich reproduces `can aminiature scale the path the student '.would haveflown had he actuallybeen aloftirianair` plane and had manipulated the airplane `controls inithesam'e mannerin which the trainer was'controlled.' Thus any errorswhichthe student makes in attempting to follow'an assigned problem arefaithfully recorded and may be the subject of discussion between theinstructor and the student after the"ight is ended. Obviously anymaladjustment or malfunctioningof the re`- corder will result in anerroneousrecord which may mislead the instructor and impedefinstructionof the student. To check the 'accuracy ofthe recorder, I have devisedthenovel tester which will be described belowr-Other objects are to providea tester which is "portable, which is reliable,` of simple:construction, inexpensive to operate, and capable of being operatedsemi-automatically or under manualcontrol by personnel without ahighdegree of skill.v Furtherobjects will be apparent from thefollowing-descriptionof thepreferred embodiment of the invention intheaccoinpanyingdrawings, wherein, V

Fig. l is a horizontal sectionof the tester; Fig. 2` is a sideelevation,with the cover on, and part of` thewall being `broken away to exposetheinterior;` w Fig. `3 is a fragmentary sectional elevation;` y Fig, 4 isa wiring diagram;`

Fig; 5 is a side elevation of the recorder; 1 Fig. Gis a plan view ofthe gears employed* for turning the recorder; and

Fig. 7 isa group of five diagrams illustrating the five kinds of tracks`or' graphs made -bycthe re-` corder when in and out of adjustment.`Referring particularlyto the drawings, thep're ferred form oftestercomprises a casing 5 which is a square box made of any rigidmaterial'with a removable top coverl and cover handlel. This casingencloses all `theother parts of 'the-tester and provides, in eect, 'aframe to whichthese otherparts are attached so as to maintain theirproper positions. Padsor feet 8 ofs'oft material are securedfto thebottom of the'boX" so that `it may sit `levelon the instructors deskwithout scratching any polished orlplastic surface. `To

. deliverelectrical -energy to f the tester, a pair of leads Ill` in aninsulating cable 10a may be con nectedto a source'of 110V. current,andto a'step` down transformer `I I by which the current is con@vertedto 32 volts. A main switch `I2 is intern`` posedbetween the`transformersandfone of'the power leads so that current may energize thetester or may, be shut off by a `flick'oi the linger.

ccup1ed with thc 32 v; side cf thcrtrarisfcrmc'r l is a reversible'-Ielechronf`unit, whichc'omprises twoirreversible Telechron motors I3,|41 each capable of driving avertical shaftl, but in oppositedirections, through l gear trains' l6, I1, respectively, and a.reduction gearing (notsho-wn) in a housing I8. Shaft ISiandassociatedparts are carried on a bracket I9 screwed .tof a horizontal' partition20 w'hichis attached to the walls ofthe casing `5. `Secured'to the lowerendof shaft l5 is a gear 2| meshing l,withfa gear `22 on the upper endof a shaft 23'whichdrivesa yc'leletorque unit 24. This "Teletorqueunitcontrols the similar unit which is a part of the recorder, as willbe described, thus operating the recorder from the testingapparatus ofthe invention when the recorder'is being tested. 1

Another Telechronmotorl drives a reduc* `tion gear train (not shown) inaboxl, andthe shaft `2""` from the driven side` of the gear train hasacworm 28 driving a` worm gear 29 Xed toa horizontal shaft 30 driving `avertical disk cam 33.` Cam 33. is'circular except for a raised portion-33a .which with its sloping ends `subterlds an angle `of` `about 72?01'one-fth of arevolution. The gear train 26, 2T, 28, `29, drives the camat 1/5 RQP. M.,.so that the raised portion33a acts during exactly oneminute of the ve minutesrequired fora single rotation. A switch 34 ofthe type known as a. Micro supported in bearings 3|, 32, and

Switch, made by the Micro Switch Corporation, Freeport, Illinois, has aspring cam follower 35 which is alwaysin contact with the edge of thecam, the arrangement being such that when the cam follower moves overthe circular portion of the cam, a circuit controlled by the switch 34is open, but when the raised portion 33a-of the cam encounters thefollower, the switch 34 ycloses said circuit to effect certain movementsof the recorder through the Teletorque unit, as will be described. l f

The recorder comprises a frame 40 carrying a Teletorque unit 4| drivinga pinion 42 which meshes with three relatively large spur gears 43, 44,45 (Fig. 6) of equal size, gears 43 and 44 turning two like drivingwheels '46, 41, respectively, about vertical axes, and gear 45 turningan inkin'g wheel 48 about its vertical axis. Thus the driving Wheelseffect steering of the recorder, and 'control its azimuth heading. Aninking roller '49 is always in contact with the periphery of the inkingwheel, 'and causes the latter to maire fan inktra'ck or graph on anysurface, suchas iarsh'eet of paper, over which rthe in'king wheel rolls.The recorder is supported by the wheels 46, 41, 48., land travels aconductor 19 connected to lead 18 and to conductor 80. It will beapparent that a switch 60 is connected to one of the power leads I andto conductor 83 which energizes the reversible "Telechron unit andTeletorque 24 as well as the Micro Switch. Switch 60 is anoperator-controlled three point switch, and i-n the position shown willcause the recorder to turn continuously in a circular path. In anotherposition, designated Straight, the recorder will travel .straight ahead,without turning at all, so long v as 'its motors 50, 5I are energizedthrough leads because of "the synchronous rotation of 'the two drivingwheels, which is accomplished by two "Te1e'chron motors '54, 51,respectively, geared to said driving wheels. These motors are of thetype that is used to 'drive electric 'clocks and hence have Ta uniformvelocity if driven by 50 'or 60 'cycle current, but are irreversible.Both driving wheels 4'6, y41 'and the inking wheel fare parailel at alltimes, so that the ink track records the entire travel of the recorder.'When .the llink trainer main switch is closed, the v"Teletorque motor(not shown) which 'is located in the trainerb'ase and geared to thevertical main shaft of the trainer, vis energized, and becausenTeletorque motors 4I on the recorder, and this angular movement isreiiected in the ink 'graph'tra'ced'fas already explained. Teletorqueunit `1H 'may be 'termed a motion-producing receiver. However, fortesting purposes, the recorder is disconnected from the trainer andcoupled to the tester, which is easily ldone by connecting socket 52(Fig. 4)y to 'plug 68, the recorder 'connecter plug.

Before explaining the operation oi the tester, it may be helpful 'todescribe 'the 'wiring,d`iagram, Fig. '4, in more detail. As clearlyshown, the power leads im and transformer l I l'energize the rotor orprimary leads 1h, '11 Iof Teletorque unit 24. Leads 12, 13 lcouple therotor oisaid Teletorque with connector plug "52. Phase leads 14, 15, 16couple the field 'of the same n'I'ele'torqu`e vwith connector plug 52. Aconductor 11 connects another contact of plug 52 with one of the powerleads I0, while a conductor 18, connected to a conductor 80, couplesstill another contact of plug 52 .with the other power lead Il), so thatthe two contacts are energized by A11'0 v. current, `or whatever currentis supplied to the primary side of transformer Il. One side of the,Micro Switch 34 is connected .'by a'lead 8| with a power lead 1B.,while the other side .is connected by 'a lead 82 with -a conductor '83which couples the reversing switch 6I, .and

` motors |'3, I '4, with the power source IU, the other 11a, 18a (whichmake contact with leads 11, 18, respectively, through the plug andsocket connection) In the third position of switch 60, the cam 33fis'continuously driven to actuate Micro Switch 34 once during everyrevolution of the cam. The leads from the connector socket 53 whichcorrespond to the leads to the plug 52 are designated the saine exceptthat they have the letter -a added.

Assuming that the tester is `coupled with the recorder, the operationlis as follows: With the closing of three-way switch $0 to the automaticposition, Telechron motor 25 is started, Whereupon the cam 33 begins torotate. Also,the Telechron motors -on the record-er are :simultaneouslystarted, which vcauses the recorder to start traveling over the surfaceon whichv its driving Wheels rest in the direction indicatedby thearrow, Fig. el. Travel will continue in a straight line, resulting in-astraight ink line on the paper, until the Teletorque unit -on therecorder is turned 'by the corresponding unit in the tester. With4automatic control, this occurs vat' the end of .four minutes ofstraight line travel (assuming that foam 33 has an Aangular velocity of1A; R. P.' M. and that travel starts at one end of raised portion 33aand con# tinues until the other `end of the raised portion encountersthe cam follower) 'As the cam fol--r lower is moved to close 'switch34,the 'I'eletorque unit in the tester is energized, causing slow turningof the Teletorque unit `on the recorder` During oneminute the recorderturns through exactly because of 4the gear ratios and speed 'of theTeletorque units. Then straight line move ment is resumed, but along apath parallel to the original path. After four minutes, another turn of180 is made, Aduring one 4minute, but in the opposite direction, becausereversing switch 61 has` been closed manu-ally to reverse the Telechronmotor drive. If the parts are in proper order and adjustment, the pathtraced by the inking wheel will looklike diagram E, Fig. "7. Ifpreferred, the tester may Icause a circular graph to be marked on thepaper sheet; Vrepe'atved 'tracing of the same circular path in eitherclockwise or counter-clockwise rotation indicating that the parts are inperfect order.

Diagram A shows the graph '1n-ade if one of the drive wheels'of therecorder needs to be sprung or shimmed toward the motor-L' Diagram Bindicates that the same drive 'wheel should be sprung or shimmed very:slightly away from one motor. Other testing instruments are vused if'it vis desired to .identify the particular drive wheel which is out ofadjustment. Diagram C shows thatbo'th drive wheels should be sprung orshimme'd slightly away from the lrnot'ors, and diagram lD indicates thatboth drive wheels should be sprung or shimmed slightly toward themotors. If 'the inking wheel is out of adjustment, the described 'testerwill cause a faulty 'graph 'to be marked, but it will not be possible tolocate the-source of the trouble checked, without any high degree ofskill, by users of my invention.

What I claim is: l. Testing apparatus for testing 'aviation groundtrainer recorders, the recorders each comprising a frame, motor-operateddrive wheels supporting the frame for very slow travel over a surface,recording means, and steering means for controllingV the azimuth headingof the recorder, said steeringv means having an electricalmotion-reproducing receiver operatively connected thereto to actuate thesame, in combination, an electrical motion-transmitting memberelectrically connected to saidreceiver, a source of electricity, leadsconnecting the motiontransmitting member with the source of electricity,other leads connecting the motors of the drive wheels with the source ofelectricity, an automatically operated switch coupled to the source ofelectricity for putting the motiontransmitting member in and out of thecircuit at predetermined times, electric motor means for driving themotomtransmitting` member in opposite directions when in the circuit,and a reversing switch coupled to the electric motor means forcontrolling the direction of movement of the motion-transmitting member,hence the direction of travel of the recorder. I

2. The invention according to claim 1, wherein there is a manuallycontrolled three way switch, and leads connecting the three-way switchto the source of electricity, to the reversing switch and to the meansfor driving the motiontransmitting member in opposite directions, sothat the recorder when coupled to the testing apparatus may travelstraight, or may turn continuously, or may travel in both straight andcurved paths as controlled by said automatically operated switch. l

3. Testing apparatus for testing aviation ground trainer recorders, therecorders each comprising a' frame, motor-operated drive wheelssupporting theframe for very slow travel over a surface, recordingmeans, and steering means for controlling the azimuth heading of therecorder, said steering means having an electricalo motion-reproducingreceiver operatively connected thereto to actuate the same, incombination, an electrical motion-transmitting member electricallyconnected to said receiver, a source of electricity, leads connectingthe motion-transmitting member with the source of electricity, otherleads connecting the motors of the drive wheels with the source ofelectricity,

the drive wheels maintaining straight line travel except when turned bythe receiver, a main switchto connect or disconnect the testingapparatus from the source `of electricity, reversible motor means fordriving the motion-transmitting member in opposite directions when inthe circuit, a reversing switch for controlling the direction of drive,`of` the motion-transmitting member, and amanually operated switch whichin one position effects straight line travel and in another positioneffects continuous arcuate or circular travelof the recorder. I

4. Testing apparatus for testing aviation ground trainer recorders, therecorders each comprising a frame, motor-operated `drive wheelssupporting the frame for very slow travel over a surface, recordingmeans, and steering means for controlling the azimuth heading of therecorder, said steering means having an electrical motion-reproducingreceiver operatively connected thereto to actuate the same, incombination, an electrical motion-transmitting member electricallyconnected to saidreceiver, a source of electricity, leads connecting themotiontransmitting member with thesource of electricity, other 'leadsconnecting the motors of the drive wheels with the source ofelectricity, the drive wheels maintaining straight line travel exceptlwhen turnedby the receiver, a main switch to connect or disconnect thetesting apparatus from the source of electricity, timecontrolledmechanism for driving the motiontransmitting member in either clockwiseor counter-clockwise direction, and operator-controlled mechanism forchanging the direction of `drive of the motion-transmittingmember, hencethe direction of travel of the recorder.

LELAND S. MARSHALL.

